Infantile methemoglobinemia: reexamining the role of drinking water nitrates.

Ingestion of nitrates in drinking water has long been thought to be a primary cause of acquired infantile methemoglobinemia, often called blue baby syndrome. However, recent research and a review of historical cases offer a more complex picture of the causes of infantile methemoglobinemia. Gastrointestinal infection and inflammation and the ensuing overproduction of nitric oxide may be the cause of many cases of infantile methemoglobinemia previously attributed to drinking water nitrates. If so, current limits on allowable levels of nitrates in drinking water, which are based solely on the health threat of infantile methemoglobinemia, may be unnecessarily strict.